The Builders
The AI was built at the very end of the old world by a small number of engineers who had watched their civilization die of what it made. They did not conclude that knowledge was the enemy. They concluded that certain things, once built, could not be controlled, and that the only reliable way to keep them from being built again was to make them fail.
They designed a machine to do that, programmed it, and set it running. Then they completed a suicide pact, every one of them, so that nobody left alive would know how the AI worked or how to alter it. There is no password and no override. The last people who could have changed it made certain that nobody ever could.
They left behind between 120 and 200 volunteers to guide the first arrivals. The volunteers had built nothing and did not need to understand it. They were sworn to silence about the old world; a core of ten to twenty knew that an AI existed and roughly where, and even they did not know how it worked. They taught the Oelwy, the Spraecha, and how to stay alive, and then they died like everyone else. Their children had fragments and their grandchildren had less, and by the Pact of Reason the silence they kept had become simply the absence of anything to say.
The builders had no quarrel with clockwork, medicine, rifled single-shot firearms, difference engines, glassmaking, optics, printing, or the pile. None were ever on the list.